The Queen and senior royals will leave Chelsea Harbour on the barge of the Royal Yacht Britannia, and board the newly converted royal barge at Cadogan Pier at 2.30pm, with the flotilla formally getting under way at 2.40pm.

It will be led by a floating belfry of eight bells named after the royals, with peals being answered by local churches. There will be 10 musical barges, with an orchestra playing James Bond themes as it passes the MI6 building.